Chamber door construction



Feb. 6, `1945. E. I oDwlG CHAMBER DOOR CONSTRUCTION Filed June 10, 1942 l Patented Feb.16, 1945 Erwin Ludwig, FranklinSquare, N. Y., a'ssignor to Mobile Refrigeration, Inc., New York, N. Y., a corporation of New York Application June 10,1942, Serial No. 446,480

4 Claims.

This invention relates to a door construction and more particularly concerns an improved door or closure for use in closed chambers in which the atmospheric pressure and temperature are varied over wide rang.

In the production of aircraft, and of instruments and devices for use thereon, it is necessary or desirable to reproduce the varying conditions of atmospheric temperature and pressure encountered in flight in order that such apparatus may be tested, calibrated and developed under conditions to which it is subjected in operation. The atmospheric conditions necessary in such work may vary from the maximum temperatures and pressures encountered at sea level to temperatures well below 100 below zero Fahrenheit and pressures below four inches of mercury absolute. Since the conditions to be produced involve sub-atmospheric pressures, the testing and development work is carried out in a closed chamber which is provided with a door to permit access to the interior of the chamber, and a sight opening or window to permit observation of the apparatus in the chamber while under low temperature and pressure conditions.

It is the object of the present invention to provide an improved door or closure for chambers of the type described which preferably incorporates a sight opening or window and forms an airtight heat insulating closure that is highly effective and at the same time simple in construction and inexpensive to manufacture and assemble. l

Other specic objects and features of the invention will be apparent from the following description of a typical embodiment thereof Which is illustrated in the accompanying drawing. In the drawing;

Fig. 1 is a sectional plan view of a chamber equipped with a door construction embodying the invention;

Fig. 2 is an elevation of the chamber opening taken along the line 2-2 of Fig. 1 and viewed in the direction of the arrows; and

Fig. 3 is an enlarged sectional view of the door and the chamber opening illustrated in Figs. 1 and 2.

Referring to the drawing, a chamber of the type generally described is illustrated in a simplilied form at C. The chamber may be of various shapes and is usually cylindrical or rectangular, the disclosed chamber being ofI rectangular form. The walls 4 of the chamber may be constructed of various materials and in the illustrated embodiment comprises spaced metal sheets connected at their edges. It will be understood that the chamber walls 4 are tightly joined by welding or other suitable means to form an airtight construction, and that the walls may be heat insulated in any suitable known manner. The chamber is provided with an opening O surroun-ded by a flange 5 which acts as the door jamb, as shown in Figs. l and 2.

The chamber may be cooled by any suitable means, and a cooling unit 6 which may comprise a refrigerant evaporator is shown in Fig. 1 for this purpose. The air pressure in the chamber may be varied by suitable means such as air pumps connected to the interior of the chamber through a duct 'I sealed in an opening through the chamber wall.

The door structure D comprises a frame 8 of rectangular form carrying spaced substantially parallel panels P and P1, preferably of glass or other transparent material, the frame being hingedly secured to the chamber C to swing over the opening O to a closed position. The central opening of the frame 8 and the inner panel P mounted therein are somewhat larger than the chamber opening O, as shown in Fig. 1. The inner panel P acts as the pressure retaining element of the door structure, and when the door is closed the inner surface of this panel directly engages a gasket 9 surrounding the chamber opening O within the frame 8. Airtight engagement between the panel P and the gasket 9 is insured by movably mounting or oating the panel in the door frame. Thus the panel P is secured to the door frame 8 *by a yielding connection that both permits movement of the panel to cooperate with the gasket 9 and insures that -despite such movement the heat insulating properties of the door structure are not impaired.

Referring more in detail to the construction illustrated, the door frame 8 may be formed of wood or other suitable material covered with a metal sheathing or armor I0. Any desired number and type of hinges may be used. In the disclosed embodiment, two hinges H of conventional form are shown, and the plates I I and I2 of each hinge are respectively secured to the chamber wall 4 and the outer edge surface of the door frame -8, as shown in Figs. 1 and 3. The plate II may be adjustably xed to the door frame 8 by bolts I3 passing through elongated openings I4 in the plate, Wing nuts I5 or other suitable means being used to hold the plate in. place. With this arrangementthe space between the door frame 8 and the chamber flange 5 may be adjusted lto accommodate gaskets of various Any suitable latches or clamps may be employed to releasably secure the door in its closed position, but it is preferred'that `these devices be of the type which forcibly press the door toward the chamber opening iange 5. In the disclosed embodiment, two clamps of conventional construction are illustrated. Each clamp comprises a bolt I6 pivotally secured to the chamber wall and movable into a slotted lug I1 fixed to theedge of the door frame 8 opposite the hinged edge thereof, and a nut |8-engaging the bolt I6 and seating on the outer surface of the lug l1, as shown in Fig. 1.

The gasket 9 surrounding the chamber opening O is preferably mounted on the flange close to the edge of the opening and is within the confines of the frame 8 when the door is closed. The gasket 9 may comprise a strip of rubber or other yieldable resilient material and it may be conveniently mounted in an outwardly opening channel or groove such as that formed by the spaced strips I9 and 20 welded or otherwise secured to the outer face of the nange 5. As shown in Figs. 1 and 3, the gasket 9 extends beyond the outer edges of the strips I9 and 29 so that an unconfined distortable portion of the gasket is presented outwardly about the opening for cooperation with the door panel P when the door is closed. The gasket 9 may comprise a single continuous strip or several strips placed in endwise abutment in the groove formed by the parts i9 and 20. A second gasket 2| is provided for engagement between the chamber opening ange 5 and the door frame 8 outside of and spaced from the air sealing gasket 9. As shown, the outer gasket 2| comprises a strip of rubber or other resilient or yieldable material vfixed by riv ets 22 to the outer face of the ange 5 near its periphery. When the door D is closed, the gaskets 9 and 2| enclose a dead air spaceA between the flange 5 and the door frame 8 and so substantially prevent heat transmission to the chamber at this point. l

Referring now to the panel construction a retainer strip 23 extends inwardly from the door frame 8 adjacent its inner face and is secured to the frame by a suitable means such as screws 24. 'Ihe strip 23 extends around the door frame opening and forms a ledge or flange for retaining the panel structure in place. The inner panel P is preferably a relatively thick pane of glass capable of withstanding Substantially full atmospheric pressure. It is movably supported or noated in the frame 8 by means of resilient gaskets. A gasket 25 is disposed between the inner face of the panel P and-the retainer strip 23, an edge gasket 28 lies between the edge of the panel and the inner surface of the frame 8,

and a gasket -21 engages the outer face of the panel P adjacent its edge, as shown. The gaskets 25, 26 and 21 are formed of resilient yieldable material such as rubber, and an integral U-section gasket may be used in place of the three separate gaskets' if desired. A spacer strip 28 extends around the inner surface of the frame 8 outside the panel P and is engaged between the outer gasket 21 of that panel and the inner gasket of the outer panel Pi. The outer panel P1 is mounted in the frame 8 in spaced substantially parallel relation to the inner panel P. I prefer to movably support the outer panel P1 in gaskets and, as shown, its edge is embraced by the gaskets f2s. so and marginal surface, its edge surface and its outer marginal surface. The outer panel Pl in the disclosed embodiment comprises a pair of parallel glass' sheets 32 and 33 connected by a spacer 34 sealed to the plates at their edges, the space between the plates being evacuated. Double sheet panels of this type have good heat insulating properties which enhance their usefulness in my construction, although outer panels of other types may be employed.

The entire panel assembly comprising the inner panel P with its gaskets 25, 26-and 21, the spacer strip 28 and the outer panel P1 with its gaskets 29, 30 and 3| is held in place within the opening of the door frame 8 by a compression ring 35 which engages the outer face of the outermost gasket 3| and is secured to the outer face of the door frame 8 by suitable means such as screws 38. The spacer strip 28 is preferably free to move-relative `to the door frame 8. The relation of the parts is such that the entire panel assembly is clamped between the compression ring 35 and the retainer strip 23, the panel gaskets being slightly compressed when the ring 35 is fixed in place. With this arrangement, the space 3l between the panels P and P1 is substantially sealed by the panel gaskets and the spacer strip 28, and acts as a dead air space to reduce heat transfer through the doorl panel structure. Also, heat transfer by air flow between the panels P or Pi and the door frame 8 is prevented by the panel gaskets. The gaskets also form cushion mountings for the panels and avoid panel breakage during assembly of the structure.

The described combination provides a simple and highly effective door structure for chambers of the type described. The inner panel P directly engages and compresses the gasket 9 and forms the pressure sealing element of the closure structure. The use of a movable panel to directly cooperate with the chamber gasket 8 and so perform the sealing function avoids the possibility of air leakage through the joints between the panels and the door frame, and further provides a selfadjusting fit between the sealing parts of the closure. The movable or oating.connection beltween the panel P and the door frame 8 permits and the necessity for close adjustment of the door hinges and clamps is avoided. The outer panel P1 cooperates with the inner panel P to provide effective thermal insulation, and the resilient yieldable seal between the panels and the door frame 8 insures that despite movement of the inner panel, air leakage andl the consequent heat transfer through the panel structure is substantially prevented.

I claim:

l. In apparatus of the type described, in combination with a chamber having an -opening therein and a resilient yieldable gasket surrounding said opening and extending outwardly therefrom, a closure for said opening comprising a frame hingedly secured to said chamber and movable to a closed position surrounding said gasket with said gasket extending into said frame, a pressure retaining panel secured to and movably mounted in said frame and engageable with the entire outer face of said gasket when said frame is in its closed position, and means for releasably clamping said frame in its closed position where- 3| which respectively engage its` innerv a tight closure said door frame, a heat insulating glass panel in l by said pane1-is pressed against saidgasket and forms a tight closure for said chamber opening.

2. In apparatus of the type described, in combination with a chamber having an opening therein and a resilient yieldable gasket surrounding said opening and extending outwardly therefrom. a closure for said opening comprising a frame hingedly secured to said chamber and movable to a closed position surrounding said gasket with said gasket extending into said frame, a

pressure retaining panel of transparent material secured to and movably mounted in said frame and engageable with the entire outer face of said gasket when said frame is in its closed position, a second panel of transparent material mounted in said frame outside of and in spaced substantially parallel relation to said pressure retaining panel,

and means for releasably clamping said frame in its closed position whereby said pressure retaining panel is pressed against said gasket and forms for said chamber opening.

3. In apparatus of the type described, in combination with a chamber having an opening therein and a yieldable resilient gasket surrounding said opening and extending outwardly therefrom, a closure comprising a door frame having a central opening, means for hingedly securing said door ,frame to said chamber to move to a closed position surrounding said gasket with said gasket extending into an inner glass panel secured in the opening of said door frame adjacent its inner face and engageable with said gasket to sea1 said chamber opening when said door frame isin its closed position, a retaining strip fixed to said door frame and extending inwardly therefrom into the door frame opening adjacent its inner face for limiting inward movement of said inner panel relative to the central opening of the frame,

said door frame opening outside of said inner panell a spacer strip disposed between said panels adjacent their edges, yieldable resilient gasket means embracing said inner panel adjacent its edge and interposed between said inner panel and said retainer strip. said door frame and said spacer strip, and means secured to said frame outside of said heat insulating panel for clamping said panels and said spacer strip together against said retaining strip.

4. In apparatus of the type described, in combination with a chamber having an opening therein and a yieldable resilient gasket surrounding said opening and extending outwardly therefrom, a closure comprising a door frame having a central opening, means for hingedly securing said door frame to said chamber vto move to a closed position surrounding said gasket with said gasket extending into the central opening of the frame, an inner glass panel secured in the opening of said door frame adjacent its inner face and engageable with said gasket to seal said chamber opening when said door frame is in its closed position, a retaining strip tlxed to said door frame and extending inwardly therefrom into the door frame opening adjacent its inner face for limiting inward movement of said inner panel relative to said door frame, a heat insulating glass panel in said door frame opening outside of said inner panel, a spacer strip disposed between said panels adjacent their edges, yieldable resilient gasket means embracing said panels adjacent their edges, and means overlying the outer surface of said heat insulating panel and secured to said frame for clamping said panels and said spacer strips together against said retaining strip.

ERWIN LODWIG. 

